1. Field of the Invention
The present invention relates to a semiconductor device having bonding pads for wire bonding, and to a method of fabricating the semiconductor device.
2. Description of the Related Art
When forming bonding pads over copper interconnects in semiconductor devices of the prior art that employ copper interconnects, the bonding portions are in some cases provided at positions that are shifted from above the copper interconnects (refer to Japanese Patent Laid-Open Publication No. 2001-15516, pp. 4-5, FIG. 2).
FIG. 1 is a sectional structural view showing an example of the construction of a semiconductor device of the prior art. Referring to FIG. 1, a plurality of copper pads are provided on copper interconnects 700 that are formed on semiconductor substrate 10, uppermost layer aluminum interconnect 730 being formed over uppermost layer copper pad 710 with barrier metal 720 interposed. Bonding portion 735 of uppermost layer aluminum interconnect 730 is at a position that is shifted with respect to copper interconnect 700. As a result, stress that occurs when bonding is exerted upon passivation insulation film 740 and interlevel dielectric film 750 that underlie bonding portion 735. The influence of stress upon copper interconnect 700 during bonding can thus be reduced and the exposure of copper interconnects 700 on the surface can be prevented.
Nevertheless, the above-described semiconductor device of the prior art has several drawbacks.
First, because this is a construction in which bonding portions are provided at positions that are shifted with respect to the copper interconnects, the area of the bonding pads is greater than for a case in which the bonding portions are provided immediately above the copper interconnects, and this construction therefore tends to increase chip size.
Further, if a low-k film that has a lower relative dielectric constant than an oxide film is present below the bonding portion, the load of a needle during probing or bonding depresses the bonding pads and may cause cracks in the interlevel dielectric film that underlies the bonding pads or may cause film to peel in the bonding pads.